Methods of operating a liquid vaporizer

ABSTRACT

The present invention is generally directed to a vaporizer with positive liquid shut-off. In one illustrative embodiment, the vaporizer is comprised of a body, a liquid inlet and a carrier gas inlet coupled to the body, a nozzle positioned within the body, the nozzle having at least one opening formed therethrough that defines a vaporized liquid exit, and a positive shut-off valve, a portion of which is adapted to engage the vaporized liquid exit of the nozzle. In another illustrative embodiment, the vaporizer is comprised of a body, a liquid inlet and a carrier gas inlet coupled to-the body and a plurality of peltier cells coupled to the body.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of application Ser. No. 10/340,976, filed Jan.13, 2003 now U.S. Pat. No.6,997,403.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally directed to the field of liquidvaporizers, and, more particularly, to a liquid vaporizer with positiveliquid shut-off.

2. Description of the Related Art

In a wafer fabrication process, a wafer is commonly subjected to processgases under pressure in the controlled environment of a process chamber.The deposition formation rate on the wafer and the etching removal ratefrom the wafer depend on the input gas flow rate of the process gasesthat enter the process chamber encapsulating the wafer.

A vapor deposition system for wafer fabrication generally includes aliquid delivery or injection system for vaporizing a liquid chemical andcarrying the vaporized liquid into the deposition process or reactionchamber for wafer processing. A typical liquid delivery system for achemical vapor deposition process manages the flow of a liquid precursoror reagent, a carrier gas, and one or more other process gases. Theliquid precursor is delivered to a vaporization device at a steady flowrate. The carrier gas is delivered to the vaporization device for mixingwith the vaporized liquid precursor. The other process gases arecombined with the mixture of the vaporized liquid precursor and carriergas for delivery to the process chamber.

A critical factor in the production of wafers with superior uniformityis the precise control of the flow rate of the delivery of the liquidprecursor into the process chamber. Irregularities in the flow rate maycause non-uniformity and erroneous deposition film thickness thatadversely affect wafer quality and acceptability. The liquid precursorflow rate is typically generated by a liquid mass flow controller thatis governed electronically by a voltage signal, such as that produced ina liquid flow meter. The accuracy of the flow rate produced by theliquid mass flow controller depends on the calibration between thevoltage signal and the actual flow rate delivered.

Many liquid vaporizers tend to trap various amounts of liquid aftervaporization processes are stopped. Such trapped liquids must generallybe flushed from the system prior to the next use of the liquid vaporizerto introduce liquids into a process chamber. Efforts have been made toreduce the volume of such trapped liquid. Such efforts include, amongother things, physically reducing the size of spaces where such liquidsmay collect.

Liquid vaporizers sometimes use piezoelectric actuators to raise orlower a ball on a valve seat in an effort to stop the flow of avaporized liquid through the vaporizer and to prevent leakage of liquidsresident within the vaporizer after vaporization processes have stopped.However, such arrangements have proven to be unsatisfactory in that theliquid still manages to seep past this sealed surface, thereby resultingin the additional accumulation of fluid that must be flushed prior tousing the vaporizer.

The present invention is directed to a method that may solve, or atleast reduce, some or all of the aforementioned problems.

SUMMARY OF THE INVENTION

The present invention is generally directed to a vaporizer with positiveliquid shut-off. In one illustrative embodiment, the vaporizer iscomprised of a body, a liquid inlet and a carrier gas inlet coupled tothe body, a nozzle positioned within the body, the nozzle having atleast one opening formed therethrough that defines a vaporized liquidexit, and a positive shut-off valve, a portion of which is adapted toengage the vaporized liquid exit of the nozzle. In some embodiments, thepositive shut-off valve is a diaphragm or bellows valve, wherein aportion of the diaphragm or bellows is adapted to sealingly engage thevaporized liquid exit of the nozzle.

In another aspect, the present invention is directed to a vaporizerhaving means for regulating the temperature of the liquid within thevaporizer. In one illustrative embodiment, a vaporizer according to thisaspect of the invention is comprised of a body, a liquid inlet and acarrier gas inlet coupled to the body and a plurality of peltier cellscoupled to the body. In further embodiments, a temperature sensingdevice is operatively coupled to the vaporizer to sense the temperatureof the liquid within the vaporizer. A controller may use this senseddata to regulate or control the power supplied to the peltier cells tothereby maintain the temperature of the liquid within a desired range.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich like reference numerals identify like elements, and in which:

FIG. 1 is a plan view of a vaporizer in accordance with one illustrativeembodiment of the present invention;

FIG. 2 is a partial, cross-sectional view of the vaporizer depicted inFIG. 1, taken along the line “2-2”;

FIG. 3 is another partial, cross-sectional view of the vaporizerdepicted in FIG. 1, taken along the line “3-3”;.

FIGS. 4A-4B are enlarged views of one illustrative embodiment of anozzle that may be employed with the present invention;

FIG. 5 is a partial, cross-sectional plan view of the vaporizer depictedin FIG. 2, taken along the line “5-5”; and

FIG. 6 is a partial, cross-sectional side view of a vaporizer inaccordance with another illustrative embodiment of the presentinvention.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and are herein described in detail. It shouldbe understood, however, that the description herein of specificembodiments is not intended to limit the invention to the particularforms disclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Illustrative embodiments of the invention are described below. In theinterest of clarity, not all features of an actual implementation aredescribed in this specification. It will of course be appreciated thatin the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

The present invention will now be described with reference to theattached figures. Although various regions and structures shown in thedrawings are depicted as having very precise, sharp configurations andprofiles, those skilled in the art recognize that, in reality, theseregions and structures may not be as precise as indicated in thedrawings. Additionally, the relative sizes of the various featuresdepicted in the drawings may be exaggerated or reduced as compared tothe size of those features in a manufactured device. Nevertheless, theattached drawings are included to describe and explain illustrativeexamples of the present invention. The words and phrases used hereinshould be understood and interpreted to have a meaning consistent withthe understanding of those words and phrases by those skilled in therelevant art. No special definition of a term or phrase, i.e., adefinition that is different from the ordinary and customary meaning asunderstood by those skilled in the art, is intended to be implied byconsistent usage of the term or phrase herein. To the extent that a termor phrase is intended to have a special meaning, i.e., a meaning otherthan that understood by skilled artisans, such a special definition willbe expressly set forth in the specification in a definitional mannerthat directly and unequivocally provides the special definition for theterm or phrase.

FIGS. 1 and 2 are, respectively, a plan view and a partialcross-sectional view of a vaporizer 10 in accordance with oneillustrative embodiment of the present invention. As shown therein, thevaporizer 10 is generally comprised of a body 12, an actuator 16, anactuator arm 18, a seal member 22, a liquid inlet 36, a carrier gasinlet 38, a vaporized liquid outlet 40 and a positive shut-off valve 34.The positive shut-off valve 34 is coupled to the body 12 of thevaporizer 10 by a plurality of fasteners 21. The vaporizer 10 furthercomprises an actuator cavity 30, a nozzle 23 having an opening 26 formedtherethrough that defines a liquid inlet 24 and a vaporized liquid exit28 (see FIGS. 4A-4B). In some embodiments, a heating element 32(schematically depicted), e.g., resistance heating rods or elements, maybe positioned adjacent the nozzle 23. In an even more specificembodiment, the heating elements 32, when employed, may be positionedadjacent the nozzle 23 near the vaporized liquid exit 28. The vaporizer10 further comprises a schematically depicted valve 33 that may be usedfor purposes described more fully herein. In some embodiments, the valve33 is at least a two-way valve.

In the embodiment depicted in FIG. 2, the positive shut-off valve 34 isa diaphragm valve and the diaphragm 34A is adapted to sealingly engagethe vaporized liquid outlet 28 of the nozzle 23. The actuator sealmember 22 is adapted to sealingly engage the liquid inlet 24 of thenozzle 23.

FIG. 3 is a partial, cross-sectional view of the vaporizer 10 depictedin FIG. 1, taken along the line “3-3.” The actuator 16, actuator arm 18and seal member 22 may be any type of mechanism that enables theactuator seal member 22 to establish a seal with the liquid inlet of thenozzle 23. In the depicted embodiment, the actuator arm 18 is adapted topivot around a pivot pin 20 that is coupled to the body 12. The actuator16 may be any type of mechanism that may be used to cause movement ofthe actuator arm 18 to accomplish the purposes described herein. In oneillustrative embodiment, the actuator 16 is a stack of piezoelectricmembers 17 that, when energized, can be used to cause relative movementbetween the seal member 22 and the liquid inlet 24, e.g., movement froma closed to an open position (or vice versa). However, as will berecognized by those skilled in the relevant art after reading theentirety of the present application, the present invention should not beconsidered as limited to the use of a piezoelectric type actuator. Theactuator cavity 30 is sized and configured such that the actuator arm 18may move freely within the actuator cavity 30 and to accommodate anyprocess fluids that may flow therethrough. Power may be supplied topiezoelectric members 17 via a conventional power source (not shown).Such piezoelectric actuators are well known to those skilled in the artand will not be described in any further detail so as not to obscure thepresent invention.

The positive shut-off valve 34 is adapted to, when actuated, provide apositive, liquid-tight seal with the vaporized liquid exit 28 of thenozzle 23. In one illustrative embodiment, the positive shut-off valve34 may be comprised of a diaphragm valve or a bellows valve. Thediaphragm valve and/or the bellows valve may be pneumatic-based devices.The diaphragm or bellows 34A may be comprised of a variety of materials,such as carbide, ruby, or a metal such as stainless steel, hastaloy,incolnel, etc. In the embodiment depicted in FIG. 2, a portion of thediaphragm 34A is, when actuated, adapted to conform to and sealinglyengage the vaporized liquid exit 28. FIGS. 4A-4B are enlarged views ofthe nozzle 23, the portion 34A of the positive shut-off valve 34, andthe seal member 22. FIG. 4A depicts the situation in which the portion34A is not sealingly engaged with the vaporized liquid outlet 28 of thenozzle 23, and the seal member 22 is not sealingly engaged with theliquid inlet 24 of the nozzle 23. FIG. 4B depicts the situation in whichboth the portion 34A and the seal member 22 are sealingly engaged to thenozzle 23. In FIG. 3, the diaphragm 34A is depicted in the situationwhere it is disengaged from the vaporized liquid exit 28 of the nozzle23.

FIG. 5 is a partial,-cross-sectional plan view of the vaporizer 10 takenalong the line “5-5” depicted in FIG. 2. As shown therein, a cavity 35is formed in the body 12 such that, if desired, carrier gas (asindicated by the arrows 37) may flow around the diaphragm 34A when it issealingly engaged to the vaporized liquid exit 28 of the nozzle 23.

FIG. 6 is a partial, cross-sectional view of an embodiment of thepresent invention wherein the positive shut-off valve 34 is a bellowsvalve. As shown therein, a portion of the bellows valve 34A is adaptedto sealingly engage the vaporized liquid exit 28.

The valve body 12 may be of any size or configuration, e.g., it may havea generally cylindrical shaped body 12, or a generally rectangularshaped body 12. The valve body 12 may be comprised of a variety ofmaterials, such as metal like stainless steel, hastaloy, incolnel, etc.Thus, the particular configuration of the body 12 and its materials ofconstruction should not be considered a limitation of the presentinvention. The overall size of the vaporizer 10 may also vary dependingupon the application. For example, in the case of a generallycylindrical shaped device, the overall diameter of the body 12 may be onthe order of approximately two inches.

The nozzle 23 may be comprised of a variety of materials, such asstainless steel, hastaloy, incolnel, etc. The size and configuration ofthe opening 26 may also vary depending upon the particular application.In one embodiment, the opening 26 may have a diameter of approximately0.005-0.050 inches and, in one particular embodiment, the diameter maybe approximately 0.010 inches. The actuator seal member 22 may becomprised of a variety of materials, such as stainless steel, hastaloy,incolnel, etc. The size, number and configuration of the heatingelements 32, if used, may vary depending on the particular application.Such heating elements 32 may be employed in situations where it isdesired to heat the liquid to reduce the viscosity of the liquid so thatit may readily flow through the opening 26 in the nozzle 23. The heatingelements 32 may also be employed in situations where it is desirable tosuperheat the liquid to some degree.

Also depicted in FIGS. 1 and 2 is another embodiment of the presentinvention wherein means for cooling the body 12 are provided. In oneembodiment, a plurality of peltier cells 44 may be coupled to the body12. The size, shape and number of the peltier cells 44 may varydepending upon the particular application and the location where coolingis desired. The peltier cells 44 may be coupled to the valve body 12 ina variety of ways as long as the peltier cells 44 can still performtheir intended function. In one illustrative embodiment, the peltiercells 44 may be coupled to the valve body 12 by mechanical fasteners.The peltier cells 44 may be coupled to an illustrative power supply 45and energized as desired to achieve the desired cooling effect. In theembodiment where the peltier cells 44 are employed, a temperaturesensing device 47, such as a thermocouple, may be operatively positionedso as to sense the temperature of liquid within the cavity 30 in thebody 12. In turn, the sensed temperature may be provided to a controller49 which regulates or controls the power supplied to the peltier cells44 such that the liquid within the cavity 30 is maintained withindesired limits. In that manner, the peltier cells 44 may be employed tokeep the vaporizer 10 at a relatively cool temperature, e.g.,approximately 30° C. Such cooling may act to keep the material in aliquid state and to prevent the material from breaking down.

One aspect of the present invention is generally directed to providing aliquid vaporizer 10, with a positive liquid shut-off mechanism. Anillustrative operational sequence for such a device will now bedescribed. Initially, with the member 34A sealingly engaged to thevaporized liquid exit 28 of the nozzle 23, a purging process isperformed by passing a carrier gas, e.g., an inert gas, helium, argon,nitrogen, etc., through the carrier gas inlet 38 and out the drain/vent.After purging operations are completed, a liquid is introduced into thevaporizer 10 via liquid inlet 36. Alternatively, liquid may still bepresent in the cavity 30 from previous use of the vaporizer 10. In someembodiments, the carrier gas may flow at a rate of approximately100-20,000 sccm.

At that time, the member 34A of the positive shut-off valve 34 isdisengaged from the vaporized liquid exit 28 of the nozzle 23. Theactuator 16 is then activated to cause the seal member 22 to moverelative to the liquid inlet 24 of the nozzle 23. The pressure withinthe cavity 30 is generally higher relative to the pressure at thevaporized liquid exit 28 of the nozzle 23. This pressure differentialmay be created by establishing vacuum conditions in the cavity 35 or bysupplying positive pressure within the actuator cavity 30.

The actuator 16 and actuator arm 18 are sized and configured such thatthe seal member 22 allows very small droplets of liquid to pass throughthe opening 26. This may be accomplished by breaking at least a portionof the seal between the seal member 22 and the liquid inlet 24 veryfrequently. For example, the actuator 16 and actuator arm 18 may beconfigured such that the seal member 22 breaks the seal with the liquidinlet 24 every 10 milliseconds. These pulses of very small liquiddroplets then exit the nozzle 23 as vaporized liquid via the vaporizedliquid exit 28. The carrier gas flowing through the vaporizer 10 maythen transport the vaporized liquid to the downstream process tool viathe vaporized liquid outlet 40. If desired, the valve 33 may bepositioned to direct flow therethrough to the drain/vent when vaporizingprocesses are being started. It can be maintained in that position untilsuch time as the appropriate process engineer is confident that thevaporizer 10 is producing the desired stream of vaporized liquid. Atthat time, the valve 33 may then be positioned such that the vaporizedliquid is directed to the downstream process tool.

To stop operation of the vaporizer 10, the following steps may be taken.Initially, the seal member 22 is sealingly engaged with the liquid inlet24 of the nozzle 23. Depending upon whether the system is designed as anormally-closed or normally-open system, the actuator 16 may or may notbe actuated. Thereafter, the member 34A of the positive shut-off valve34 may be actuated so as to sealingly engage the vaporized liquid exit28 of the nozzle 23. This may be accomplished by supplying theappropriate fluid, e.g., air pressure, to the positive shut-off valve34. Then, carrier gas may be passed through the vaporizer 10 and out thedrain/vent to flush out the vaporizer 10 of any remnants of thevaporization process.

In one aspect, the present invention is generally directed to avaporizer with positive liquid shut-off. In one illustrative embodiment,the vaporizer is comprised of a body, a liquid inlet and a carrier gasinlet coupled to the body, a nozzle positioned within the body, thenozzle having at least one opening formed therethrough that defines avaporized liquid exit, and a positive shut-off valve, a portion of whichis adapted to engage the vaporized liquid exit of the nozzle. In someembodiments, the positive shut-off valve is a diaphragm or bellowsvalve, wherein a portion of the diaphragm or bellows is adapted tosealingly engage the vaporized liquid exit 28 of the nozzle 23.

In another aspect, the present invention is directed to a vaporizerhaving means for regulating the temperature of the liquid within thevaporizer. In one illustrative embodiment, a vaporizer according to thisaspect of the invention is comprised of a body, a liquid inlet and acarrier gas inlet coupled to the body and a plurality of peltier cellscoupled to the body. In further embodiments, a temperature sensingdevice is operatively coupled to the vaporizer to sense the temperatureof the liquid within the vaporizer. A controller may use this senseddata to regulate or control the power supplied to the peltier cells 44to thereby maintain the temperature of the liquid within a desiredrange.

The particular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. For example, the process steps set forth above may beperformed in a different order. Furthermore, no limitations are intendedto the details of construction or design herein shown, other than asdescribed in the claims below. It is therefore evident that theparticular embodiments disclosed above may be altered or modified andall such variations are considered within the scope and spirit of theinvention. Accordingly, the protection sought herein is as set forth inthe claims below.

1. A method of operating a liquid vaporizer, comprising: introducing a liquid to be vaporized into a cavity of said vaporizer, said vaporizer comprising a nozzle, said nozzle having at least one opening formed therethrough that defines a vaporized liquid exit and a liquid inlet of said nozzle, said liquid inlet being separated from the cavity by a seal; cooling said liquid in the cavity prior to vaporizing the liquid; repeatedly breaking the seal multiple times per second to allow droplets of the cooled liquid to enter the liquid inlet; and vaporizing said cooled liquid droplets in the nozzle.
 2. The method of claim 1, further comprising introducing said vaporized cooled liquid into a processing tool.
 3. The method of claim 1, wherein cooling said liquid comprises energizing at least one peltier cell to cool said liquid.
 4. The method of claim 3, wherein said at least one peltier cell is operatively coupled to a body of said vaporizer.
 5. The method of claim 1, further comprising: sensing a temperature of said fluid in said vaporizer; and maintaining said temperature of said fluid within an allowable range.
 6. The method of claim 1, wherein said vaporizer comprises a body, said cavity comprising a first cavity, said body comprising a second cavity formed therein, said first cavity adapted to contain at least a portion of said liquid to be vaporized in said vaporizer, said liquid inlet being positioned in said first cavity, and wherein said cooling said liquid comprises cooling said liquid in said first cavity prior to introducing said liquid into said liquid inlet of said nozzle.
 7. The method of claim 1, wherein said vaporizer further comprises at least one heating element positioned adjacent said nozzle, and wherein said method further comprises energizing said at least one heating element to heat the liquid droplets flowing in said nozzle.
 8. A method of operating a liquid vaporizer, comprising: introducing a liquid to be vaporized into a cavity of said vaporizer, said vaporizer comprising a nozzle, said nozzle having at least one opening formed therethrough that defines a vaporized liquid exit and a liquid inlet of said nozzle, said liquid inlet being separated from the cavity by a seal; coolinq said liquid in the cavity prior to vaporizinq the liquid; repeatedly breaking the seal to allow droplets of the cooled liquid to enter the liquid inlet; vaporizing said cooled liquid droplets in the nozzle; and actuating a positive shut-off valve to sealingly engage said vaporized liquid exit of said nozzle to prevent flow of vaporized liquid therethrough.
 9. A method of operating a liquid vaporizer, comprising: introducing a liquid to be vaporized into a cavity of said vaporizer, said vaporizer comprising a nozzle, said nozzle having at least one opening formed therethrough that defines a vaporized liquid exit and a liquid inlet of said nozzle, said liquid inlet being separated from the cavity by a seal; sensing a temperature of said liquid; cooling said liquid in the cavity prior to vaporizing the liquid in response to said sensed temperature; repeatedly breaking the seal multiple times per second to allow droplets of the cooled liquid to enter the liquid inlet; and vaporizing said cooled liquid droplets.
 10. The method of claim 9, further comprising introducing said vaporized cooled liquid into a processing tool.
 11. The method of claim 9, wherein cooling said liquid comprises energizing at least one peltier cell to cool said liquid.
 12. The method of claim 11, wherein said at least one peltier cell is operatively coupled to a body of said vaporizer.
 13. The method of claim 9, wherein said sensing a temperature of said fluid in said vaporizer comprises sensing a temperature of said fluid within said cavity.
 14. The method of claim 13, further comprising maintaining said sensed temperature of said fluid within an allowable range.
 15. The method of claim 9, wherein said sensing a temperature of said liquid comprises sensing a temperature of said liquid prior to introducing said liquid into said liquid inlet of said nozzle.
 16. The method of claim 9, wherein said cooling said liquid comprises cooling said liquid prior to introducing said liquid into said liquid inlet of said nozzle.
 17. The method of claim 9, wherein said vaporizer comprises a body, said cavity comprising a first cavity, said body comprising a second cavity formed therein, said first cavity adapted to contain at least a portion of said liquid to be vaporized in said vaporizer, said liquid inlet being positioned in said first cavity, and wherein said cooling said liquid comprises cooling said liquid in said first cavity prior to introducing said liquid into said liquid inlet of said nozzle.
 18. The method of claim 16, wherein said vaporizer further comprises at least one heating element positioned adjacent said nozzle, and wherein said method further comprises energizing said at least one heating element to heat the liquid droplets flowing in said nozzle.
 19. A method of operating a liquid vaporizer, comprising: introducing a liquid to be vaporized into a cavity of said vaporizer, said vaporizer comprising a nozzle, said nozzle having at least one opening formed therethrough that defines a vaporized liquid exit and a liquid inlet of said nozzle, said liquid inlet being separated from the cavity by a seal; sensing a temperature of said liquid; cooling said liquid in the cavity prior to vaporizing the liquid in response to said sensed temperature; repeatedly breaking the seal to allow droplets of the cooled liquid to enter the liquid inlet; vaporizing said cooled liquid droplets; and actuating a positive shut-off valve to sealingly engage said vaporized liquid exit of said nozzle to prevent flow of vaporized liquid therethrough.
 20. A method of operating a liquid vaporizer, comprising: introducing a liquid to be vaporized into said vaporizer, said vaporizer comprising a nozzle, said nozzle having at least one opening formed therethrough that defines a vaporized liquid exit and a liquid inlet of said nozzle; energizing at least one peltier cell to cool said liquid prior to introducing said liquid into said liquid inlet of said nozzle; repeatedly breaking a seal multiple times a second to allow droplets of the cooled liquid to enter the liquid inlet; and vaporizing said cooled liquid droplets.
 21. The method of claim 20, further comprising introducing said vaporized cooled liquid into a processing tool.
 22. The method of claim 20, wherein said at least one peltier cell is operatively coupled to a body of said vaporizer.
 23. The method of claim 20, further comprising: sensing a temperature of said fluid in said vaporizer; and maintaining said temperature of said fluid within an allowable range.
 24. The method of claim 20, wherein said vaporizer comprises a body, said body having a first cavity and a second cavity formed therein, said first cavity adapted to contain at least a portion of said liquid to be vaporized in said vaporizer, said nozzle having at least one opening formed therethrough that defines a vaporized liquid exit and a liquid inlet of said nozzle, said liquid inlet being positioned in said first cavity, and wherein said energizing said at least one peltier cell to cool said liquid comprises energizing said at least one peltier cell to cool said liquid in said first cavity prior to introducing said liquid into said liquid inlet of said nozzle.
 25. The method of claim 20, wherein said vaporizer further comprises at least one heating element positioned adjacent said nozzle, and wherein said method further comprises energizing said at least one heating element to heat the liquid droplets flowing in said nozzle.
 26. A method of operating a liquid vaporizer, comprising: introducing a liquid to be vaporized into said vaporizer, said vaporizer comprising a nozzle, said nozzle having at least one opening formed therethrough that defines a vaporized liquid exit and a liquid inlet of said nozzle; energizing at least one peltier cell to cool said liquid prior to introducing said liquid into said liquid inlet of said nozzle; repeatedly breaking a seal to allow droplets of the cooled liquid to enter the liquid inlet; vaporizing said cooled liquid droplets; and actuating a positive shut-off valve to sealingly engage said vaporized liquid exit of said nozzle to prevent flow of vaporized liquid therethrough.
 27. A method of operating a liquid vaporizer, comprising: introducing a liquid to be vaporized into a first cavity formed in a body of said vaporizer; sensing a temperature of said liquid within said first cavity; cooling said liquid in response to said sensed temperature; repeatedly breaking a seal multiple times a second to allow droplets of the cooled liquid to enter the liquid inlet; and vaporizing said cooled liquid droplets.
 28. The method of claim 27, further comprising introducing said vaporized cooled liquid into a processing tool.
 29. The method of claim 27, wherein cooling said liquid comprises energizing at least one peltier cell to cool said liquid.
 30. The method of claim 29, wherein said at least one peltier cell is operatively coupled to said body of said vaporizer.
 31. The method of claim 27, further comprising maintaining said sensed temperature of said fluid within an allowable range.
 32. The method of claim 27, wherein said vaporizer comprises a nozzle, said nozzle having at least one opening formed therethrough that defines a vaporized liquid exit and a liquid inlet of said nozzle, and wherein said sensing a temperature of said liquid comprises sensing a temperature of said liquid prior to introducing said liquid into said liquid inlet of said nozzle.
 33. The method of claim 27, wherein said vaporizer comprises a nozzle, said nozzle having at least one opening formed therethrough that defines a vaporized liquid exit and a liquid inlet of said nozzle, and wherein said cooling said liquid comprises cooling said liquid prior to introducing said liquid into said liquid inlet of said nozzle.
 34. The method of claim 33, wherein said vaporizer further comprises at least one heating element positioned adjacent said nozzle, and wherein said method further comprises energizing said at least one heating element to heat the liquid droplets flowing in said nozzle.
 35. A method of operating a liquid vaporizer, comprising: introducing a liquid to be vaporized into a first cavity formed in a body of said vaporizer; sensing a temperature of said liquid within said first cavity; cooling said liquid in response to said sensed temperature; repeatedly breaking a seal multiple times a second to allow droplets of the cooled liquid to enter the liquid inlet; vaporizing said cooled liquid droplets; and said vaporizer further comprising a nozzle, said nozzle having a vaporized liquid exit, and said method further comprises actuating a positive shut-off valve to sealingly engage said vaporized liquid exit of said nozzle to prevent flow of vaporized liquid therethrough.
 36. A method of operating a liquid vaporizer, comprising: introducing a liquid to be vaporized into a first cavity formed in a body of said vaporizer, said body having at least one peltier cell operatively coupled thereto; sensing a temperature of said liquid within said first cavity; energizing said at least one peltier cell to maintain said temperature of said fluid in said first cavity within an allowable range; repeatedly breaking a seal multiple times a second to allow droplets of the cooled liquid to exit the first cavity; and vaporizing said cooled liquid droplets.
 37. The method of claim 36, further comprising introducing said vaporized cooled liquid into a processing tool.
 38. The method of claim 36, wherein said vaporizer further comprises at least one heating element positioned adjacent said nozzle, and wherein said method further comprises actuating said at least one heating element to heat the liquid droplets flowing in said nozzle.
 39. A method of operating a liquid vaporizer, comprising: introducing a liquid to be vaporized into a first cavity formed in a body of said vaporizer, said body having at least one peltier cell operatively coupled thereto; sensing a temperature of said liquid within said first cavity; energizing said at least one peltier cell to maintain said temperature of said fluid in said first cavity within an allowable range; repeatedly breaking a seal to allow droplets of the cooled liquid to exit the first cavity; vaporizing said cooled liquid droplets; and said vaporizer further comprises a nozzle, said nozzle having a vaporized liquid exit, and said method further comprises actuating a positive shut-off valve to sealingly engage said vaporized liquid exit of said nozzle to prevent flow of vaporized liquid therethrough. 